1. Field of the Invention
This invention relates to refrigeration apparatus and in particular to a liner construction for use therein.
2. Description of the Prior Art
One conventional method of forming a refrigeration appliance cabinet is to provide an inner liner wall and an outwardly spaced outer cabinet wall. Insulation is provided in the space between the two walls by foaming in place a foam insulation material, such as polyurethane. A problem arises in conventional such cabinet constructions in that the foamed-in-place insulation tends to adhere to the liner wall. The liner wall is conventionally formed of a synthetic resin, such as high impact polystyrene (HIPS), Acrylonitrile-butadiene-styrene (ABS), etc. resins. The adhesion of the foamed-in-place insulation to the synthetic resin liner wall may cause stress cracking thereof as a result of the differential thermal expansion of the insulation and liner wall plastic material.
It has, therefore, been proposed to apply a foam release agent to the liner wall subsequent to the forming thereof into the liner configuration. Such application of the foam release agent is relatively expensive requiring additional steps in the manufacturing process and involving additional relatively expensive labor. The provision of the foam release agent on the formed liner is illustrated in the U.S. Letters Patent of Keith K. Kesling U.S. Pat. Nos. 3,078,003 and 3,294,462, Colin S. Hocking et al. U.S. Pat. No. 3,150,796, and Paul E. Kronenberger U.S. Pat. No. 3,719,303. As disclosed therein, the protective layer may be applied to selective portions of the liner as desired.